Mobile devices often include a haptic system that is configured to provide a tactile feedback sensation such as a vibration or other physical sensation to a user touching or holding the mobile device. The haptic system can include an input surface and one or more actuators, such as piezoelectric transducers, electromechanical devices, and/or other vibration inducing devices, that are mechanically connected to the input surface. Drive electronics coupled to the one or more actuators cause the actuators to induce a vibratory response into the input surface, providing a tactile sensation to a user touching or holding the device. A conventional haptic system may include a mass in a housing that moves or oscillates to induce the vibratory response. A transducer can be included in the housing that varies its output voltage in response to changes in a magnetic field as the mass moves within the housing. The output voltage can be used in a control application to determine the position of the mass which can be used by the control application to provide stability to the haptic system.